Ammonia storage system

• US 20100172816A1
• Filed: 12/15/2009
• Published: 07/08/2010
• Est. Priority Date: 01/02/2009
• Status: Active Grant

• Current Assignee: Sensirion AG (Sensirion Holding AG)
• Original Assignee: Sensirion AG (Sensirion Holding AG)
• Inventors: Hornung, Mark, Gerner, Pascal, Mayer, Felix, Bürgi, Lukas
• Granted Patent: US 8,771,598 B2
• Time in Patent Office: Days
• US Class Current: 423/352
• CPC Class Codes: F01N 2560/023 for measuring or detecting HC
• CPC Class Codes: F01N 2560/025 for measuring or detecting O2, e.g. lambda sensors
• CPC Class Codes: F01N 2610/14 Arrangements for the supply of substances, e.g. conduits
• CPC Class Codes: F01N 2610/1406 Storage means for substances, e.g. tanks or reservoirs
• CPC Class Codes: F01N 3/2066 Selective catalytic reduction [SCR]
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A system for storing ammonia comprises gas detector that is able to detect gases other than ammonia. The system further comprises thermally activatable ammonia stores, which can be activated to release ammonia upon heating. When the ammonia stores are not heated, the system is below ambient pressure and any leak will cause external gas to enter the system. Therefore, the gas detector is used to detect the presence of such external gas, which allows to detect leaks. The gas detector may be embodied as a thermal detector using a single heater and two temperature sensors for detecting a gas flow as well as external gas.

Claims

1. An ammonia storage system comprising a thermally activatable ammonia store, which, upon thermal activation, releases ammonia into an ammonia containing section of said system, and a gas detector adapted to detect a presence of a gas other than ammonia in said ammonia containing section.

2. The ammonia storage system of claim 1 wherein said gas detector is a thermal detector measuring a parameter depending on one of a thermal conductivity and a heat capacity of gas in said ammonia containing section.

3. The ammonia storage system of claim 2 comprising a flow detector in a duct of said ammonia containing section for measuring a gas flow in said duct.

4. The ammonia storage system of claim 3 comprising a thermal flow detector comprising a heater, wherein said heater is common to said flow detector and said gas detector.

5. The ammonia storage system of claim 4 comprising at least one temperature sensor adapted to measure a temperature change induced by said heater, wherein said temperature sensor is common to said flow detector and said gas detector.

6. The ammonia storage system of claim 5 comprising at least a first and a second temperature sensor located at different positions in respect to said heater.

7. The ammonia storage system of claim 6 further comprising a control unit designed for calculating said gas flow by using a difference between signals from said first and said second temperature sensor and designed for detecting the presence of a gas other than ammonia from the signal of at least one of said temperature sensors.

8. The ammonia storage system of claim 7 wherein said control unit is designed for detecting the presence of a gas other than ammonia by using a sum of signals from said first and said second temperature sensor.

9. The ammonia storage system of claim 3 further comprising

a valve at a downstream location from said flow detector and

a system controller adapted to detect a leak downstream from said flow detector by detecting a non-zero flow at said flow detector when said valve is closed.

10. A method for operating the ammonia storage system of claim 1 wherein said gas detector is operated at least when said ammonia store is not being activated in order to detect said gas other than ammonia.

11. The method of claim 10 wherein a thermal flow detector in a duct of said ammonia containing section is used for measuring an ammonia flow in said duct as well as for detecting said gas other than ammonia.

12. The method of claim 11 wherein said flow detector is used for measuring a leak downstream from said flow detector by detecting a non-zero flow or a downstream-upstream flow.

13. Use of the system of claim 1 as an ammonia source in a vehicle.